Wireless telephones are devices capable of transmitting and receiving voice and/or data (non-voice) information to and from a network without the use of wires, cables, or other tangible transmission media. So-called cellular telephones are a common example of wireless phones.
Wireless telephones and the networks by which they communicate operate according to various technologies, including analog mobile phone service (AMPS), circuit switching, packet switching, wireless local area network (WLAN) protocols such as IEEE 802.11 compliant networks, wireless wide-area networks (WWAN), short-range RF systems such as Bluetooth, code division multiple access (CDMA), time division multiple access (TDMA), frequency-division multiplexing (FDM), spread-spectrum, global system for mobile communications (GSM), high-speed circuit-switched data (HCSD), general packet radio system (GPRS), enhanced data GSM environment (EDGE), and universal mobile telecommunications service (UMTS). Of course, these are only examples, and other technologies may be employed in wireless communication as well.
Herein, the term ‘wireless device’ is meant to include wireless telephones (including cellular, mobile, and satellite telephones), and also to include a variety of other wireless devices, including wireless web-access telephones, automobile, laptop, and desktop computers that communicate wirelessly, and wireless personal digital assistants (PDAs). In general, the term ‘wireless device’ refers to any device with wireless communication capabilities.
Many companies produce wireless telephones and other wireless devices. Among the more well-known producers are Nokia®, Ericsson®, Motorola®, Panasonic®, Palm® Computer, and Handspring®. A variety of producers also provide wireless devices comprising versions of the Microsoft® Windows® operating software.
A mobile device, also called mobile equipment, is a portable communication device that typically, but not necessarily, is also a wireless device. Laptop computers are examples of mobile devices. A “subscriber” represents one or more persons or entities (corporations, partnerships, agents, operators, etc.) with access privileges to a network. A subscriber may be or represent a single person, or may represent more than one person. Typically the subscriber is the operator of a mobile device.
A subscriber may enter into contractual arrangements with a network operator for access rights to the operator's network(s). Networks of this operator are the subscriber's “home networks.” Networks other than the home networks of the subscriber are “roaming networks.” A subscriber may gain access to roaming networks to make and receive communications, however, such access is typically provided on a per-usage basis (as opposed to a subscription basis common on home networks) and at an additional charge. Such additional charges are “roaming charges”.
One situation in which roaming charges may occur involves call forwarding. When a subscriber is roaming, calls to the subscriber may be forwarded conditionally when the subscriber's mobile device is busy (forward busy), or does not answer (forward no-answer), or rejects the incoming call (e.g. forward do-not-disturb). An incoming call is routed through the subscriber's home network, from which point the call is routed to the roaming network that is currently providing access to the subscriber. The roaming network then routes the call back to the home network, to a specified forwarding number. The subscriber thus incurs charges from both the home network and the roaming network, even though they don't answer the call. Furthermore, important call information may be lost by routing through the roaming network in this fashion. This can create problems in certain situations, such as when the call is forwarded to a voice mail system (VMS). Without certain call information, the VMS may not have the capability to intelligently select a voice mail box for the called party.